Combustion-controlling apparatus



July 2, 1929., E, ROUCKA 1.719.139

COMBUSTION CONTROLLING APPARATUS Filed Jan. 5, 1928 5 sheets-sheet 1` @i i l July 2, 1929 E. ROUCKA 1.719.139

COMBUSTION CONTROLLNG APPARATUS Filed Jan. 5, 1928 3 sheets-sheet 2 FURNACE j PRESSURE FLUE CAS PRESSURE A'rroHA/Ers.

July 2, 1929. E. ROU'KA COMBUSTION CONTROLLTNG APPARATUS Filed Jan. 5 1928 5 Sheets-Sheet N70/Mfrs.

`Patented `luly 2, 1 929.

UNITED STATES.

1,719,132@ PATENT GFFICE.

ERICH ROUKA, OF BLANSKO, CZECHOSLOVAKIA..

COMBUSTION-CONTROLLING APPARATUS.

Application led January 5, 1928, Serial No. 244,590, and in Germany January 6, 1927.

This invention relates in general to apparatus for controlling combustion, and more particularly to -such apparatus especially adapted for use with steam generating b011- ers. The apparatus is in general of the type wherein the combustion is controlled in accordance with a condition which Varies with the heat demand on the furnace, for example, steam flow, steam pressure, gas pressure, temperature, electricenergy, or an auxiliary quantity or condition which varies in accordance with the primary quantity, for example, auxiliary fluid pressure, auxiliary electric current, etc. The condition variable in accordance with the heat demand actuates a system which is movably responsive to said condition and which cooperates with another system movably responsive'to the draft in the furnace under control. I desire it to be understood that the word draft is intended to include not only the simple pressure of air or flue gases, but also the pressure difference caused by the flow of air or the liow of flue gases or by the fric.- tion of flowing liuid, or a combination of two or more of these conditions; and the word draft as used in the claims should beso construed.

One object of the invention is to provide uneans for controlling combustion in one, `or

some, or all furnaces of a battery or range at a predetermined very low or subnormal adjustable minimum and constant load as distinguished from the minimum' load under normal operation, whereby great economy in operation and consumption of fuel is attained, and the furnace is at all times in condition. for immediately assuming the respective part of the variable normal load demand.

The invention consists in providingmeans for disconnecting the means responsive to the condition variable in accordance with the heat demand from the draft responsive means, -whereby the rate of'combustion may be controlled without effect thereon by the variations in the heat demand. Upon such disconnection, the draft responsive means alone controls the variations in the draft so as to maintain a predetermined minimum damping draft which is also maintained constant. stan# draft is such as to preventl the escape of combustion gases outwardly through the cracks in the boiler walls and also to prevent drawing of excess cool4 air into the boiler Preferably this minimum con- In another arrangement for automatic control, the depression or negative pressure in the furnace chamber is regulated by another damper actuatin regulator controlled by said depression. here the furnace to be controlled operates with natural draft, the ash pit is provided with hermetical doors which are manually closed by the fireman, the degree of opening of the doors predetermining `the amount of the minimum of the load on the furnace with the fires damped. In steam boilers it is ossible to reduce the steam production uring the damped period to zero, and cause a low rate of combustion just suiiicient to produce heat necessary for compensating the heat losses and to maintain the desired steam pressure on the line.

In the accompanying 'drawing I have schematically illustrated several embodiments of my invention, but it will be under stood ,that this is primarily for the purpose of illustrating the principles of the invention, and that the invention may be embodied in different apparatus and the details of construction modified or changed by those skilled in the art without departing from the spirit or scope of the invention.

In said drawings, in which corresponding and like parts lare designated throughout the several views by thesame reference characters, y

Figure 1 is a schematic side elevation of one form of apparatus 4embodying my invention, showing the parts in the position for controlling the rate of combustion in accordance with the heat demand on the furnace;

Figure 2 is a View of the controlling a paratus illustrated in Figure 1,' showing t e parts in the position to disconnect the heat demand responsive means from the draft responsive means;

Figure 3 shows a modified form of controlling apparatus with the parts inthe pbsition shown in Figure 1;

Figure 4 is a View of the apparatus illustrated in Figure 3, showing the parts in positions corresponding to those in Figure 2, an

Figure 5 is a schematic side elevation of .apparatus embodying another modification o the uptake flue has a damper 12 which is actuated by a fluid operated motor 14, flow of fluid to and from which is controlled by a governor valve 16.

The reference charac*l *r 18 designates the main header of the boiler or battery of boilers, the pressure'in which acts through aA pipe 19 u on bellows diaphragm 20 against the in uence of a counterweight 22, part of the weight of which is balanced by the steam pressure in the diaphragm 20 and the remainder by the draft forces acting on the diaphragm 24 which is connected through a rod 32 and a lever 26 fulcrumed upon a lever 28, to the rod 29 connected to the diaphragm 20. The position of the fulcrum roller 28 is adjustable longitudinally of the lever 26 by a screw 30. The governor 16 is connected to the rod 32 by an arm 34 so that upon movement of the rod 32 the governor is actuated. To the rod 32 is connected a cross-head 36 to one end of which is connected one end of a tension spring 38 the/other end of which is adjustably connected to a fixed support as at 39. Another tension spring 40 has one end connected for movement in one direction relatively to the cross-head, as at 64, and its other end adjustably connected as at 42 to one end of a lever 44y which is pivoted intermediate its ends to a fixed support as at 46, and to which is connected a spring 48 for influencing the lever in opposition to the tension of the spring 40,A the spring 48 normally holding the lever 44 in engagement with a stop 50.

In accordance with the invention, the rod 29 is formed with an extension 52 upon which is journaled a roller 54 which follows a cam 56, so that when the cam 56 is rotated vin the direction of the arrow the weight 22 is raised an'd the lever 26 is elevated from the fulcrum roller 28, whereby the heat demand responsive means 20 is disconnected from the draft responsive means 24, as shown in Figure 2.

The end of the lever 44 opposite the spring 40 is provided with a roller 60 which follows a cam 58 similar to the cam 56 which may be mounted upon the same shaft so both said cams may be actuated simultaneously.

When the cam 58 is rotated in the direction of the arrow the lever 44 is swung against i the influence of the spring 48 so as to relieve the cross-head 36 of the tension of the spring 40, as shown in Figure 2.

he apparatus includes means whereby the draft responsive means 24 may be subjected to the pressure of the combustion gases in the furnace chamber only, or to the difference between said pressure and the pressure of the flue gases in the uptake flue. This 'means is shown as comprising a draft switch which includes a cylindrical hollow easing to which is connected at spaced points in its periphery pipes 66 and G8 which are also connected respectively at points 7 6 and 78 to the uptake flue and to the combus` tion chamber 2. The casing 70 has also connected thereto pipes 21 and 23 which are also connected to opposite sides of the diaphragm 24. Within the casing 70 is a rotatable val re plug 72 having two peripheral passages 71 and 73 cooperating with the connections to the casing 70 of the pipes GG, 68 and 21, 23. 'lhe casing 70 also has another port 8() leading to the atmosphere. The. valve plug 72 is operated by an arm 74 to which is connected a counterweight 75 and a cable 86 passing over a pulley 87 and having connected at one end a. weight 88 formed with a loop adapted to take over a hook 90. Preferably the valve plug 72 is connected to the same shaft as the cams 5G and 58 for simultaneous actuation of the draft switch and the two cams.

With the parts as shown in Figure 1 ol the drawings, the bottom side of' the diaphragm 24 is subjected to pressure of (he flue gases at the point 76, while the upper side of the diaphgram 24 is subjected to the pressure of the combustion gases at the point 78. When the cable 86'is pulled by the fireman and hooked upon the hook 90, the valve plug 72 is rotated into the position shown in Figure 2, whereupon the lower side of the diaphragm 24 is subjected to the pressure of the combustion gases in the furnace chamber at point 78, while the other side of the diaphragm is exposed to the atmosphere.

In the operation of the apparatus so far described, with minimum heat demand and normal service, the weight 22 is completely balanced by the diaphragm 20. The springs 38 and 40 are adjusted so that the sum of the tensions thereof balance the minimum pressure difference on the diaphragm 24. If this pressure difference for some reason increases, the force exerted on the diaphragm 24 overcomes the forces exerted .by the springs 38 and 40, and the rod 32 is moved to actuate the governor 16 which in turn causes the pilot motor to move the damper l2 toward closed position to decrease the pressure difference. When the pressure difference decreases a reverse operation takes place and the damper will be actuated toward open position until balance of the parts is again restored.

Upon an increasein the heat demand, for instance an increase in the discharge of steam, the pressure drop between the boilers and the main header 18 increases because of greater flow of steam and the resistances to flow formed by the tubes, superheaters, valves, etc., and the difference of the force exerted by the steam in the diaphragm 20 and the weight 22 acts on the lever 26 against the inliuence of the forces acting on the diaphragm 2 4 so as to actuate the governor 16 and cause the damper 12 to be opened. This increases the pressure difference between the points 76 and 78, which condition continues until the pressure difference acting on the diaphragm 24 again balances the ditferenceof lforces exerted by the weight 22 and the steam in the diaphragm 20. A decrease in the heat demand results in the pressure in the bellows diaphragm 20 increasing, so that the lever 26 is operated to act-nate the governor 16 so as to move the damper 12 toward closed position, whereupon the draft decreases until the diii'erence in pressure onthe diaphragm 24 again balances the resultant force exerted by the weight 22 and the steam pressure in the bellows diaphra 20.

Should it be desired to place the boiler at the constant minimum damping load according to the invention, the fireman will hook the loop ofthe Weight 8 over the hook 90, as shown in Figure-2, whereupon the rollers 54 and 60 are pushed by their repective cams 56 and 58 to break the contact between the lever 26 and the fulcrum roller 28, so that the variations in the steam pressure in the bellows diaphragm 20 no longer affect the diaphragm 24. At the saine time, the spring 40 isA released, which leaves the tension of the spring 38, which is set to the desired damping draft, to balance the diaphragm 24. The draft switch 70, 72 is also operated at the same time, so that the flue gas pressure is disconnected from the diaphragm 24, the upper surface of the diaphragm 24 is exposed to the atmosphere, and the lower surface of the diaphragm 24 -subjected to the pressure of the combustion less, more air is drawn into the furnace and the draft at point 78 decreases (the absolute pressure increases). This causes the control apparatus to move the damper 12 to-ward open position so as to permit this excess of pressure to escape and to again restore the pressure. at the point 78 to the desired minimum. As the ash pit damper is closed, the

inlet of air to the furnace chamber is restricted, and consequently a greater vacuum at point 78 is produced which causes the control apparatus to move the damper 12 toward closed position to restore the pressure at the point 78 to the desired minimum.

Obviously, the operation of the draft switch 70, 72 and the cams 56, 58 may be accomplished in other ways than by the cable 86 and need not be simultaneous, as described. For example, suitable apparatus such at Huid pressure motors, electric motors, etc., might be used for operating the switch and cams from a distance and/or independently of each other. It was found that the connection 78 is best when placed at the highest point in the combustion chamber,

but it can be located at any other desired` place.

In some cases it is not necessary to utilize pressure diierence between the points 7 6 and 78 for the controlling operation, and under such circumstances the control apparatus may be simplified by using the diaphragm connected during normal operation to the -flue gases at point 76 only. Where it is desired to use only flue gas pressure for controlling purposes, it is possible to substitute a bell 82 immersed in a liquid in a container 84 and direct the controlling pressure under the bell. The draft switch under such circumstances is much simpler, as shown in Figures 3 and 4, and is so connected to the bell 82 and the points 76 and 78 that the bell 82 is subjected during normal operation to the Hue gas pressure at point 76 and during the damping period to the furnace pressure at point 78. The draft switch 72 is of course somewhat different in construction from the switch 70, 72, the valve plug having only one passage 71l to alternately connect the furnace pressure and the flue gas pressure to the bell 82. In Figure 3 of the drawings the bell is shown as connectedy to the flue gas pressure, while in Figure 4 the position of the switch is such as to connect the bell to the furnace pressure at point 7 8. It is also possible for some purposes to completely eliminate the draft switch and utilize only the flue gas pressure at point 76 for the controlling operation, this flue gas pressure being varied during normal operation in accordance with the heat demand and'being maintained constant during the damping period to keep the lire damped.

Figure 5 illustrates another form of my invention wherein the condition variable in accordance with the heat demand, that is in this case the steam pressure in the header 102, is translated into the variable position of the rod 104. The steam pressure acts on the diaphragm 106 and is balanced by the lever 108 having the counterweight 110 thereon and a spring 112 which has one end l116 is thus actuated and permits the flow of fluid to and from the pilot motor 114 so that the rod 104 is actuated in the direction of the arrow which diminishes the force of the spring 112 until balance is again restored between the pressure at 106 and the forces exerted by the weight 110 and spring 112. Upon a decrease in the load a reverse action takes place. Therefore, each position of the rod 104 corresponds to a certain pressure at 106. l

The rod 104 actuates a movable fulcrum roller 122 beneath a lever 124, one end of which is connected by a link 128 to a diaphragm 146 one side of which is subjected to pressure-of the flue gases at point 160 in the furnace, while the other side is exposed to the atmosphere. The other end of said lever 124 has a yoke 126 pvotally connected thereto intermediate its ends, one endof said yoke having connected thereto one end of a 'tension spring 130, the other end of which is connected to a rod 136 adjustable in a fixed bracket 138 and held in adjusted position by a set screw 140.- Adjustable collars 142 and 144 on said rod limit the adjusting movements thereof. The other end of the yoke 126 has connected thereto one end of a tension spring 132 which is of less tension than the spring 130, and which has its other end adjustably connected as at 134 to a fixed support. These two springs are normally so adjusted relatively to each other that the difference intension thereof exerts a force in the direction of the arrow, thatis, so that the spring 130 normally overcomes the tension ofthe spring 132. The arm 148 is connected to the rod 128 and controls the How of fluid to and from a pilot motor 152 which' actuates the uptake fine damper 154. To this arm 148 is also connected a tension spring 158 which is adjustable at 156. This spring 158 partially balances the force exerted on the diaphragm 146B and is adjusted to predetermine the minimum draft during the controlling operation.

Obviously, movement of the roller 122 will affect the balance of the forces exertedy 'by the diaphragm 146 and the spring 158 on one end of the lever, and the orces exerted by thegsprings 132 and 130 on the other end of the lever, and therefore the difference ,between the forces exerted by the springs 130 and 132 exerts a force on the link 128 which is in accordance with the heat demand. The governor 150 accordingly controls the pilot motor 152 so as to vary the draft at point 160 in accordance with the heat demand. In other words, an increase in the load or heat demand on the furnace moving the roller 122 will cause actuation of the governor valve 150 in the ydirection of the arrow by the spring 130 so that the damper 154 is opened to decrease the pressure at 160 and increase `the flow of gases through the furnace; while upon a decrease in the load the roller 122 is moved in the other direction and the damper 154 is moved toward closed position to decrease the flow of flue gases through the furnace.

When it is desired to damp the furnace so as to maintain a constant minimum draft in accordance with the invention, the set screw 140 is loosened and the rod 146 permitted to move in the direction of the pull of the spring 130 until the collar 144 en` gages the bracket 138. This reduces the tension of the spring 130 so that it is overcome by the spring 132, which draws the lever 124 out of contact with the fulcrum roller 122 and into contact with alixed fulcrum roller 162. The sprin 132 then exerts a force on the rod 128 in t e reverse direction to that previously exerted by the spring 130, and this force exerted by the s ring 130 partially overcomes the force o the spring 158. The resultant force then alone balances the force exerted on the diaphragm 146 by the pressure at the point 160, and predetermines the amount of the draft which it is desired to maintain at the point 160 during the damping period. In other words, during the damped period the pressure is maintained at the point 160 at a minimum predeterminedv by the resultant force `derived from the coo eration of the springs 132 and 158 througii the lever 124 and the fulcrum 162. An increase in pressure at point 160 causes movement of the governor valve 150 in the direction of the arrow which produces actuation of the damper 154 toward open position to decrease said pressure; and a decrease in pressure at the point A160 causes a reverse operation and a movement of the damper 154 toward closed position.

Having thus described the invention, what I claim is:

1. In combustion controlling apparatus, the combinationfwith a passageway for the incoming air and the combustion gases including a combustion chamber, of a damper in said passageway,`a pilot motor for operating said damper, a governor for said motor. means movably responsive to variations in the draft'through said passageway for actuating said governor to maintain a constant draft, means movably res onsive to a condition variable according to cheat T demand, means operatively connecting the second responsive means tothe first responsive means so that said governor is actuated jointly by both said responsive means to vary the draft according to the heat demand, and means operable independently of the heat demand for manipulating said connecting means to disconnect said two responsive means from each other.

2. In combustion controlling apparatus, the combination with a passageway for the incoming air andthe combustion gases including a combustion chamber, of a damper in said passageway, a pilot motor for operating said damper, a governor for said' pilot motor, means movably responsive to variations in the draft, means movably responsive to a condition variable according to the heat demand cooperating with the first responsive means and said governor to actuate said governor according to the heat demand, and means actuated independently of the heat demand 'for interrupting cooperation of said two responsive means so that after such interruption said governor is actuated only by the first responsive means to maintain a constant draft independent of the heat demand.

3. In combustion controlling apparatus, the combination with a passageway for the incoming air and the combustion gases including a combustion chamber, of a damper in said passageway, a pilot motor for operating said damper, a governor' for said pilot motor, means movably responsive to variations in the draft, means movably responsive to a condition variable according to the heat demand cooperating with the first responsive means and said governor to actuate said governor according to the heat demand, means actuated independently of the heat demand for interrupting cooperation of said two responsive means so that after such interruption said governor is actuated only by the first responsive means to maintain a constant draft independent of the heat demand, and means for applying an adjustable mechanical force to the first responsive means to predetermine the constant draft conditions to be maintained.

4. In combustion controlling apparatus, the combination wtih a passageway for the incoming air and the combustion gases including a combustion chamber, of a damper in said passageway, a pilot motor for operating said damper, a governor for said motor, means movably responsive to variations in the draft through said passageway for actuating said governor' to maintain a constant draft, means movablyresponsive to a con.

dition variable according to the heat demand, means operatively connecting the second responsive means to the first responsive means so that said governor is actuated jointly by both said responsive means to vary the draft according to the heat demand, means operable independently of the heat demand for manipulating said connecting means to disconnect said two responsive means from each other, and means for changing the draft connections between said passageway and said first responsive means.

5. In combustion controlling apparatus, the combination with a passageway for the incoming air and the combustion gases including a combustion chamber,'of a damper lin said passageway, a pilot motor for operating said damper, a governor for said motor,

`means to disconnect said two responsive means from each other, and means for changing the draft connection between said passageway and said first responsive means so that the draft will be maintained constant at the point in said passageway where the pressureis highest at damped load. 6. In combustion controlling apparatus, the combination with a passageway for the incoming air and the combustion gases including a combustion chamber, of a damper in said passageway, a pilot motor for operating said damper, a governor for said motor, means movably responsive to variations in the draft through said passageway for actuating said governor to maintain a constant draft, means movably responsive to a condition variable according to the heat demand, means operatively connecting the second responsive means to the first responsive means so that said governor is actuated jointly by both said responsive means to vary the draft according to the'heat demand, means operable independently of the heat demand for manipulating said connecting means to disconnect said two responsive means from each other, means for applying an adjustable mechanical force to the first responsive means to predetermine the constant draft conditions to be maintained, and means for changing the draft connections between said passageway and said first responsive means. 7 In combustion controlling apparatus, the combination with a passageway for the incoming air and the combustion gases including a combustion chamber, of a damper in said passageway, a pilot motor for operating said damper, a governor for said motor, means movably responsive to variations in the draft through said passageway for acmand, means actuated tuating said governor to maintain a constant draft, means movably responsive to a condition variable according to the heat demand, means operatively connecting the second responsive means to the first responsive means so that said governor is actuated jointly by both said responsive means to vary the draft according to the heat demand, means operable independently of the heat demand for `manipulating said connecting means to disconnect said two responsive means from each other, means for applying an adjustable mechanical force to the first responsive means to predetermine the constant draft conditions to be maintained, and means for changing the draft connections between said passageway and said first responsive means so that the draft will be maintained constant at the point in said passageway where the pressure is highest at damped load.

8. In combustion controlling apparatus, the combination with a passageway for the incoming air and the combustion gases including a combustion chamber, of a damper in said passageway, a pilot motor for operating said damper, motor, means movably responsive to variations in the draft, means movably responsive to a condition variable according to the heat demand for cooperating with the first responsive means and said governor to actuate said governor according to the heat deindependently of the heat demand for interrupting cooperation of said two responsive means so that after such interruption said governor is actuated only by the first responsive means to maintain a constant draft independent of the heat demand, means for applying an adjustable mechanical force to the first responsive means to predetermine the constant draft conditions to be maintained, and common means for simultaneously actuating said means for interrupting cooperation of said two responsive means and adjusting said means for applying a mechanical force.l

In combustion controlling apparatus,

' the combination with a passageway for the incoming air and the combustion gases including a combustion chamber, of a damper in saidpassageway, a pilot motor for operating said damper, a governor for said pilot motor, variations in the draft, means lmovably responsive to a condition variable according to the heat demand cooperating with the first responsive means and said governor to actuate said governor according to the heat demand, means actuated independently of the heat demand for interrupting cooperation of said two responsive means so that after such interruption said governor is actuated only by the first responsive means a governor for said pilotmeans movably responsive 'tov to maintain a constant draft independent of the heat demand, means for applying an adjustable mechanical force to the first responsive means to predetermine the constant draft conditions to be maintained, common means for simultaneously actuating said means for interrupting cooperation of said two responsive means and adjusting said means for applying a mechanical force, and means for changing the draft connections between said passageway and said first responsive means.

10. In combustion controlling apparatus, the combination with a passageway for the incoming air and the combustion gases including a combustion chamber, of a damper in said passageway, a pilot motor for operating said damper, a governor for said motor, means movably responsive to variations actuating said governor to maintain a constant draft, means movably responsive to a condition variable according to the heat demand, means operatively connecting the second responsive means to the first responsive means so that said governor is actuated jointly by both said responsive means to vary the draft according to the heat demand, means operable independentl of the heat demand for manipulating sai connecting means to disconnect said two responsive means from each other, means for changing the draft connections between said passageway and said first responsive means, and means for simultaneously actuating the last-named means and said means for interrupting actuation of said two responsive means.

11. In combustion controlling apparatus, the combination with a passageway for the incoming air and the combustion gases including a combustion chamber, of a damper in said passageway, a pilot motor for operating said damper, a governor for said motor, means movably responsive to variations 1n the draft through said passageway for acin the draft through said passageway for l tuating said governor to maintain a constant draft, means movably responsive to a condition variable according to the heat demand, means operatively connecting the second responsive means to the first responsive means so that said governor is actuated jointl bv both said responsive means to vary the (ii Laccording to the heat demand, means operable independently of the heat demand for manipulating said connecting means to disconnect said two responsive-means from each other, means for applying an adjustable mechanical force to the first responsive means to predetermine the constant draft conditions to b e maintained, means for changing the draft connections between said passageway and said first responsive means, and means for simultaneously actuating the last-named means and said means for interrupting actuaft ation of said two responsive means and ,ad-

`justing said means for applying a mechanil@ motor, means movably responsive' to variations in the draft, means movably responsive to a condition variable according to the heat demand cooperating with the first responsive means and said governor to aetnate said governor according to the heat demand, and

means for changing the draft connections between sald passageway and said lrst responsive means.

ERICH ROUKA. 

